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Detection rules › Sigma

WMI Module Loaded By Uncommon Process

Status
test
Severity
low
Log source
product windows, category image_load
Author
Roberto Rodriguez @Cyb3rWard0g
Source
github.com/SigmaHQ/sigma

Detects WMI modules being loaded by an uncommon process

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1047 Windows Management Instrumentation

Event coverage

ProviderEventTitle
SysmonEvent ID 7Image loaded

Rule body yaml

title: WMI Module Loaded By Uncommon Process
id: 671bb7e3-a020-4824-a00e-2ee5b55f385e
status: test
description: Detects WMI modules being loaded by an uncommon process
references:
    - https://threathunterplaybook.com/hunts/windows/190811-WMIModuleLoad/notebook.html
author: Roberto Rodriguez @Cyb3rWard0g
date: 2019-08-10
modified: 2025-02-24
tags:
    - attack.execution
    - attack.t1047
    - detection.threat-hunting
logsource:
    category: image_load
    product: windows
detection:
    selection:
        ImageLoaded|endswith:
            - '\fastprox.dll'
            - '\wbemcomn.dll'
            - '\wbemprox.dll'
            - '\wbemsvc.dll'
            - '\WmiApRpl.dll'
            - '\wmiclnt.dll'
            - '\WMINet_Utils.dll'
            - '\wmiprov.dll'
            - '\wmiutils.dll'
    filter_main_generic:
        Image|contains:
            - ':\Program Files (x86)\'
            - ':\Program Files\'
            - ':\Windows\explorer.exe'
            - ':\Windows\Microsoft.NET\Framework\'
            - ':\Windows\Microsoft.NET\FrameworkArm\'
            - ':\Windows\Microsoft.NET\FrameworkArm64\'
            - ':\Windows\Microsoft.NET\Framework64\'
            - ':\Windows\System32\'
            - ':\Windows\SysWOW64\'
    filter_optional_other:
        Image|endswith:
            - '\WindowsAzureGuestAgent.exe'
            - '\WaAppAgent.exe'
    filter_optional_thor:
        Image|endswith:
            - '\thor.exe'
            - '\thor64.exe'
    filter_optional_defender:
        Image|endswith: '\MsMpEng.exe'
    filter_optional_teams:
        Image|contains:
            - '\Microsoft\Teams\current\Teams.exe'
            - '\Microsoft\Teams\Update.exe'
    filter_optional_sysmon:
        Image|endswith:
            - ':\Windows\Sysmon.exe'
            - ':\Windows\Sysmon64.exe'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: low

Stages and Predicates

Stage 0: condition

selection and not 1 of filter_main_* and not 1 of filter_optional_*

Stage 1: selection

selection:
    ImageLoaded|endswith:
        - '\fastprox.dll'
        - '\wbemcomn.dll'
        - '\wbemprox.dll'
        - '\wbemsvc.dll'
        - '\WmiApRpl.dll'
        - '\wmiclnt.dll'
        - '\WMINet_Utils.dll'
        - '\wmiprov.dll'
        - '\wmiutils.dll'

Stage 2: not filter_main_generic

filter_main_generic:
    Image|contains:
        - ':\Program Files (x86)\'
        - ':\Program Files\'
        - ':\Windows\explorer.exe'
        - ':\Windows\Microsoft.NET\Framework\'
        - ':\Windows\Microsoft.NET\FrameworkArm\'
        - ':\Windows\Microsoft.NET\FrameworkArm64\'
        - ':\Windows\Microsoft.NET\Framework64\'
        - ':\Windows\System32\'
        - ':\Windows\SysWOW64\'

Stage 3: not filter_optional_*

filter_optional_other:
    Image|endswith:
        - '\WindowsAzureGuestAgent.exe'
        - '\WaAppAgent.exe'
filter_optional_thor:
    Image|endswith:
        - '\thor.exe'
        - '\thor64.exe'
filter_optional_defender:
    Image|endswith: '\MsMpEng.exe'
filter_optional_teams:
    Image|contains:
        - '\Microsoft\Teams\current\Teams.exe'
        - '\Microsoft\Teams\Update.exe'
filter_optional_sysmon:
    Image|endswith:
        - ':\Windows\Sysmon.exe'
        - ':\Windows\Sysmon64.exe'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
Imagematch:\Program Files (x86)\
Imagematch:\Program Files\
Imagematch:\Windows\Microsoft.NET\Framework64\
Imagematch:\Windows\Microsoft.NET\FrameworkArm64\
Imagematch:\Windows\Microsoft.NET\FrameworkArm\
Imagematch:\Windows\Microsoft.NET\Framework\
Imagematch:\Windows\SysWOW64\
Imagematch:\Windows\System32\
Imagematch:\Windows\explorer.exe
Imageends_with:\Windows\Sysmon.exe
Imageends_with:\Windows\Sysmon64.exe
Imageends_with\MsMpEng.exe
Imageends_with\WaAppAgent.exe
Imageends_with\WindowsAzureGuestAgent.exe
Imageends_with\thor.exe
Imageends_with\thor64.exe
Imagematch\Microsoft\Teams\Update.exe
Imagematch\Microsoft\Teams\current\Teams.exe

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
ImageLoadedends_with
  • \WMINet_Utils.dll corpus 2 (sigma 2)
  • \WmiApRpl.dll corpus 2 (sigma 2)
  • \fastprox.dll corpus 3 (sigma 3)
  • \wbemcomn.dll corpus 3 (sigma 3)
  • \wbemprox.dll corpus 2 (sigma 2)
  • \wbemsvc.dll corpus 3 (sigma 3)
  • \wmiclnt.dll corpus 3 (sigma 3)
  • \wmiprov.dll corpus 2 (sigma 2)
  • \wmiutils.dll corpus 3 (sigma 3)